1. Field of the Invention
The present invention relates generally to data storage devices for digital computers, and more specifically to adapting data storage devices for installation within a limited amount of space.
2. Description of the Prior Art
Some models of peripheral devices used in digital computer systems, such as disk drives, employ a type of electrical connector called a Single Connector Attachment (xe2x80x9cSCAxe2x80x9d). In numerous ways, the electrical signals used for disk drives having an SCA are included among those specified for a conventional American National Standards Institute (xe2x80x9cANSIxe2x80x9d) Small Computer System Interface (xe2x80x9cSCSIxe2x80x9d) bus. However, the connector of a SCA disk drive, which couples the disk drive to a computer system, is mechanically from a conventional SCSI bus connector. For example, the SCA connector, in addition to electrical contacts for SCSI bus control and data signals, also includes electrical contacts that couple all electrical power to the disk drive. Conversely, conventional electrical connectors for the SCSI bus do not carry electrical power for energizing a disk drive""s operation. Moreover, a SCA peripheral device omits some facilities, such as an ability to specify a SCSI ID bit, that must be included in a SCSI peripheral device.
Despite these incompatibilities between a SCA peripheral device and a SCSI peripheral device, at times it can become commercially advantageous to incorporate a SCA disk drive into a computer system that employs only conventional SCSI bus connectors. FIG. 1 depicts a prior art adapter-assembly, referred to by the general reference character 10, that permits such an adaptation. As depicted in FIG. 1, the adapter-assembly 10 includes a female SCA connector 12 that mates with a male SCA connector included in a SCA disk drive 14, that is not visible in any of the FIGs. The female SCA connector 12 is mounted co-planarly on and electrically interconnected to a printed circuit board 16. Also mounted along an edge 18 of and electrically connected to the printed circuit board 16 are both an conventional SCSI bus connector 22 and a conventional 4-pin electrical-power connector 24. Electrically conductive traces included in the printed circuit board 16, that are not separately depicted in FIG. 1, interconnect the female SCA connector 12 with the conventional SCSI bus connector 22 and the 4-pin electrical-power connector 24. These electrically conductive traces are arranged so the SCA disk drive 14 operates properly if the female SCA connector 12 is mated with the SCA disk drive 14, and a SCSI cable and an electrical power cable, not depicted in any of the FIGS., are respectively mated with the conventional SCSI bus connector 22 and with the 4-pin electrical-power connector 24.
However, while the prior art adapter-assembly 10 illustrated in FIG. 1 permits the SCA disk drive 14 to operate properly when connected to a computer system that employs only conventional SCSI bus connectors, a SCA disk drive 14 combined with the adapter-assembly 10 is physically longer than the space usually provided within such a computer system for a disk drive. Consequently, the prior art adapter-assembly 10, depicted in FIG. 1, addresses only the electrical problems of incorporating the SCA disk drive 14 into a computer system, while ignoring mechanical problems inherent in such an adaptation of the SCA disk drive 14.
In addition to the excessively large amount of space required by the adapter-assembly 10, the adapter-assembly 10 provides only limited compatibility with the ANSI SCSI standards. In 1986 ANSI first adopted a SCSI-I standard, and then several years later ANSI adopted a SCSI-II standard. A major objective of the SCSI-II standard is maintaining backward compatibility with those SCSI-I devices that support bus parity, and that conform to level 2 of the SCSI-1 standard. In practical terms, such backward compatibility means that, despite differences between the SCSI-I and SCSI-II standards, various SCSI-I devices operate properly if connected to a SCSI-II bus, and conversely. However, while maintaining this backward compatibility, the SCSI-II standard also permitted an additional style of connector which does not mate with the SCSI-I standard""s single style of connector. The structure of the prior art adapter-assembly 10 that is depicted in FIG. 1 can accommodate only a single conventional SCSI bus connector 22 of either style. Consequently, the adapter-assembly 10 inherently possesses only a limited capability for mating with conventional SCSI-II connectors.
An object of the present invention is to provide an improved adapter for interconnecting a peripheral device that employs a SCA connector, such as a disk drive, with a conventional SCSI bus.
Another object of the present invention is to provide a more compact adapter for interconnecting a peripheral device that employs a SCA connector, such as a disk drive, with a conventional SCSI bus.
Another object of the present invention is to provide an adapter for interconnecting a peripheral device that employs a SCA connector, such as a disk drive, with a conventional SCSI bus through more than a single style of conventional SCSI bus connector.
Another object of the present invention is to provide a more compact adapter for interconnecting a peripheral device that employs a SCA connector, such as a disk drive, with a conventional SCSI bus through more than a single style of conventional SCSI bus connector.
Briefly, the present invention is a compact adapter for interconnecting a digital computer peripheral device that uses a SCA, such as a disk drive, to a conventional SCSI bus. The compact adapter includes a SCA connector adapted to mate with and engage a complementary, male SCA connector included in the peripheral device. The SCA connector is juxtaposed perpendicularly with a first face of a planar printed circuit board. The printed circuit board includes traces that electrically couple the printed circuit board to the SCA connector. To permit a disk drive, together with a mated compact adapter, to fit within a space in a digital computer system that is adapted to receive the peripheral device, the printed circuit board is formed with a narrow width parallel to the first face of the printed circuit board and perpendicular to a longitudinal axis of the SCA connector.
The compact adapter also includes an electrical power connector that is juxtaposed with and disposed perpendicular to a second face of the printed circuit board opposite to the first face to which the SCA connector juxtaposes. Traces on the printed circuit board electrically couple the electrical power connector to the SCA connector.
The compact adapter also includes a first, conventional SCSI bus connector having a style chosen from among a plurality of styles permitted for conventional SCSI-II bus connectors, The SCSI bus connector is juxtaposed with and disposed perpendicular to the second face of the printed circuit board. The SCSI bus connector is also electrically coupled to the SCA connector by traces on the printed circuit board.
In a preferred embodiment, the compact adapter includes a second, conventional SCSI-II bus connector having a style, chosen from among the plurality of styles for conventional SCSI bus connectors, that differs from the style of the first, conventional SCSI bus connector. The second SCSI bus connector is also juxtaposed with and disposed perpendicular to the second face of the printed circuit board, and electrically coupled to the SCA connector by traces on the printed circuit board.
These and other features, objects and advantages will be understood or apparent to those of ordinary skill in the art from the following detailed description of the preferred embodiment as illustrated in the various drawing figures.